Building GHC in under 10 minutes

People often complain at how long the GHC build process can be. This is even more of an issue for developers working on libraries, or the compiler itself, who need to quickly check their code typechecks and links inside the glorious maze that is GHC’s builds system.

With the fairly recent GNU make -j fixes, and a decent multicore machine, you can cut your build times dramatically. Here’s a transcript, with some hints on getting fast turnarounds from GHC builds: